The available spectrum for two-way mobile radio systems is limited in today's regulatory environment. Spectrum re-allocations, re-banding, and re-purposing are becoming significantly more common in several radio frequency (RF) bands. Cellular carrier spectrum use (due, at least in part, to the smartphone revolution) is consuming large quantities of spectrum, leaving relatively less spectrum available for two-way mobile radio uses. This reduction in available Land Mobile Radio (LMR) spectral resources and spectrum use will most likely continue to increase in the future (due to ongoing severe spectrum shortages), and will challenge both two-way mobile radio users and manufacturers.
Engineering solutions that improve the spectral efficiency of two-way mobile radio channels are considered valuable to both regulators and network operators. Indeed, it often occurs that regulators pressure LMR-equipment manufacturers to either improve spectrum-utilization efficiency or risk losing allocated spectrum. Increased spectral efficiency also helps to improve both voice capacity and effective data-transfer rates in LMR systems, which among other advances could help to extend the useful life of such systems, and could provide moderate-rate data services in areas where broadband access is unavailable, potentially extending the markets for LMR equipment. Accordingly, for these reasons and others, there is a need for methods and systems for dynamically adjusting frequency offsets for mitigating interference.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.